Conventional semiconductor wire bonders use X-Y tables to move the bond head over the semiconductor device for bonding lead wires between the semiconductor device and its leadframe fingers. Sometimes the leadframe is replaced by other appropriate electrical connections such as a ceramic package, hybrid circuit, or other semiconductor device. The X-Y coordinate tables are driven by complex mechanical components that convert the rotary motion of the axis drive motor to controlled linear motion. Typical mechanical components may include lead screws, ball nuts, encoders, shaft and thrust bearings, and couplings, all of which reduce mechanical reliability. The bond head moved by conventional X-Y coordinate tables, carries several components such as a Z-axis drive motor, a camera for vision functions, and other components required to bond the lead wires. Such components add weight to the moving bond head, reducing maximum available table acceleration, and induce vibrations on stopping, which also increases bonding time and limits the bonder productivity. Conventional bond heads also employ flex pivots, shaft and bearings, or other point flex mechanisms to produce Z-axis motion through an arc which only allows the bond tool to be square to the bonding surfaces at only one bonding height. This inability to be square at all bonding heights causes bonding problems as the die and lead fingers are usually at different heights due to product requirements, which is further complicated by thickness variations of die, die bond material and the leadframe.
In other bonders, the X-Y table may be driven by linear motors or voice coil motors. Voice coil motors simplify gearing required by other motor drives, and eliminates ball-screw drives and slides used on some conventional X-Y tables.